Device for propelling a ship



Aug. 9, 1955 w PLEUGER ET AL 2,714,866

DEVICE FOR PROPELLING A SHIP Filed Feb. 19, 1951 2 Sheets-Sheet 1 2e 27 32 I6 I5 3O 30 25 33 34 2 [I 2| '8 k \I IN VENTORS v FRIEDRICH W. PLEUGER a FRIEDRICH F. BUSMANN ATTORNEYJ' Aug. 9, 1955 F. w. PLEUGER E AL 2,714,866

DEVICE FOR PROPELLING A SHIP Filed Feb. 19, 1951 2 Sheets-Sheet 2 FIG.6

FIGS

IN VENTORS FRIEDRICH w. P'LEUGER a FRIEDRICH F. BUSMANN BY 0M 411% ATTORNEYS United States Patent Office 2,714,866 Patented Aug. 9, 1955 DEVICE FOR PROPELLING A SHIP Friedrich W. Pleuger, Hamburg-Wandsbek, and Friedrich F. Busmann, Hamburg-Blankenese, Germany Application February 19, 1951, Serial No. 211,592 8 Claims. Cl. 115-35 Our invention relates to improvements in driving ships, and refers more particularly to a driving device consisting of an electric motor driving a propeller and fastened to the exterior of the body of the ship.

One object of our invention is to provide an electrical drive operating in such manner that the motor may work properly under water.

Another object of our invention is to provide a propeller drive of such nature that the thrust or traction produced by the propeller is most efiiciently transmitted to the body of the ship.

Another object of our invention is to provide a drive for the propeller which operates in such manner that even deep sea ships are capable of proper manoeuvring in narrow waters, such as canals etc. For this purpose the motor is enclosed in a gondola-like casing placed at the exterior of the body of the ship so that the motor immersed in water works properly and an efiicient steerage of the ship is secured.

Further objects of our invention will appear from the following description and drawings.

in the accompanying drawings, which form part of the instant specification and are to be read in conjunction therewith, and in which like reference numerals are used to indicate like parts in the various views,

Figure 1 is a magnified section through an electric motor for driving a propeller.

Figure 2 is a magnified longitudinal section through another modification of the motor driving a propeller.

Figure 3 is a side view on the stern of a ship with another modification of the propeller drive.

Figure 4 is a side view on the stern of a ship provided with a further modification of our invention.

Figure 5 is a side view on the stern of a tow-boat with a driving device for the propeller according to our invention, arranged in the rudder blade.

Figure 6 is a side view partly in section of a somewhat different construction.

Referring now to Figure 1, a part 3 of a casing is shaped like a pipe hanger, and the tubular casing 6 of an electric motor is lodged therein; the motor is placed below the water line and drives a propeller 27, either side of the body of the ship being furnished with the above mentioned assembly near the stern.

As shown in Figure 1 in a longitudinal section, the electric motor is a three phase A. C. motor, the stator laminations 8 of which are enclosed by the tubular casing 6 and comprise the windings 7, which are provided with waterproof insulation. The rotor 9 of the motor is provided with a squirrel cage and is fastened to a hollow shaft 10. On both ends this shaft is guided by slide bearings 11 and 12, which are imbedded in the hearing cases 13 and 14, connected to the casing 6. The front end of the hollow shaft -looking from the bow of the ship-carries the disk 15 of an elastic clutch; the other part of this clutch is fastened to a shaft 17 within the hollow shaft 10. On its front end said shaft 17 is guided by a slide bearing 18 placed in the bearing case 19. Besides, the shaft 17 has a disk 20 of a thrust bearing, which is supported by the two guiding members 21 and 22. The guiding member 21 is lodged in the bearing case 19, and the guiding member 22 in a bearing case 23, which is fastened to the bearing case 14 and besides is in connection with the bearing case 19.

The rear end of shaft 17 is guided in a slide bearing 24, the case of which is fastened to the bearing case 13. The hub 26 of the propeller 27 is tightened to the rear end of shaft 17.

The waterproof insulated windings 7 of the stator laminations 8 are connected to a three phase A. C. generator by means of an electric cable 28. Said generator may be arranged at any place in the body of the ship and is driven by an internal combustion motor, e. g. by a dieselmotor. The cable 28 is fastened to the support 2, which is of streamlined section.

By means of a tube 30, either side of the motor casing 6 is connected to a fresh water tank mounted in the body of the ship or on its deck. By this arrangement the inner portion of the motor is filled with fresh water. This water may flow to each bearing and lubricate it by passing through holes 31 in the bearing case 14, holes 32 in the bearing case 22, and holes 33 in the bearing case 19. The fresh water tank is placed above the water ine so as to secure a pressure of the water within the motor exceeding the static pressure of the water flowing externally around the motor. Thereby this latter water is prevented from penetrating the motor from the outside; thus the motor works properly, even when operated in sea water, as each bearing is lubricated properly. Furthermore, the motor is well cooled by the water, particularly if a permanent circular run of the water through the motor is maintained. This may be accomplished by employing one of the tubes 30 for the fresh water inlet, the other for its outlet.

The hollow motor shaft 10 is coupled to the propeller shaft 17, being guided separately by the elastic clutch 15, 16, therefore the thrust of the propeller is kept away from the rotor. As the clutch 15, 16 is situated on the remote side of the motorlooking from the side of the propeller-a very solid construction, because of its small axial length, is provided. Due to the separate bedding and the elastic clutch uniform rotation of the motor shafts is assured, therefore it can well be protected against outside water, thus the impurities of this Water cannot penetrate into the motor.

As disclosed in Figure l, the motor casing and bearing cases 14, 19, 23, and 25 in connection with it are provided with an even, streamlined exterior form, the front portion-looking from the bow of the shipbeing closed by a calotte 35, which is fastened to the bearing case 19. The form of the hub 26 of the propeller 27 is streamlined, like the gondola-like casing. The external diameter of the propeller 27 is approximately 2.5 times longer than the diameter of the motor casing 6 or of the casing portion 3 surrounding it. Since the motor is operating at high revolutions this diameter of the propeller causes peripheral speeds ranging within allowed limits; thus the propeller, on account of its relatively short blades, has a good efficiency in spite of the high motor revolutions.

By means of the disk 20 of the thrust bearing the thrust brought forth by the propeller 27 is transmitted to the gondola-like casing 3, and from this casing through the support 2 to the body 1 of the ship; in this way the entire force of the propeller is employed in driving the ship. Owing to the elongated form of easing 3, its resistance in the water is limited, therefore this driving set is working extremely economically.

Referring now to Figure 2, showing another modification of our invention in a longitudinal section; on its front end the hollow motor shaft 10, by means of a key 41, is firmly linked up with the propeller shaft 42, which is lodged within the hollow motor shaft in the same manner as shown in Figure 1. The front end of the hollow motor shaft 19 is guided in a slide bearing 43 placed in a bearing support 44, which is fastened to the motor casing 6 and the gondola-like casing 3. The disk 45 of a thrust bearing is fastened to the front end of propeller shaft 42 by means of an axial screw 46. A cylindrical joint piece 47 which is attached to the disk 45 of the thrust bearing projects into a groove of the hollow shaft 10, thereby centering both shafts 10 and 42 in relation to each other. The disk 45 is in engagement with supports 48 and 49, the former of which is tightened to the bearing case 44, the latter to the callotte 50 of the bearing, which simultaneously forms the head of the casing. It is unnecessary to provide a special bearing for the propeller shaft 42, as its front end is supported by the joint piece of the disk 45 in the hollow shaft 10. The rear end of shaft 42, carrying the propeller 27, is guided in the same bearing 24 as shown in Fig. 1.

Two motors for driving the ship may be provided at the body of the ship near its stern, one at either side. The axles of both these motors may extend parallel to the longitudinal axis of the ship. By this arrangement the thrust of both propellers is equably transmitted to the body of the ship.

The ten gondola-like driving casings, which limit the water resistance to a low range due to their elongated form, may be provided parallel to the water lines of the ship so as to be accommodated to the form of the ship and its position in the water. It is to be understood that the two axles of the propellers extend at an angle.

Figure 3 of the drawings shows an assembly as a further modification of our invention. In this drawing the propeller 71 is placed at the front end of the motor casing 72, said casing being fastened to the vertical rudder shaft 73, which is journaled at the stern of the ship and can be turned by means of the rudder helm 74. The shaft 73, which on its lower end projects out of the body of the ship, is held in place by a trunk 75 with streamlined profile, which is fastened to the body of the ship. In order to improve the steering efficiency, a flat joint piece 76 is provided on the upper side of the motor casing 72 in a longitudinal direction, which joint piece encloses the lower end of the rudder shaft and has a streamlined profile. A second flat joint piece 77 of streamlined profile is attached to the lower side of the motor casing 72.

The sphere of the water flowing into the operation field of propeller 71, which is placed before the motor casing 72, is indicated by dotted lines 78; the water stream leaving the operation field of the propeller, upon small initial contraction, is prevented from further contraction by the streamlined motor casing 72, and after having passed the casing it retains approximately the same diameter as before.

The joint pieces 76 and 77, which are attached to the motor casing 72, improve the rudder assembly since by this enlargement of the rudder surface certain steering possibilities are available if the motor driving the propeller is damaged. Thus the ship retains a certain maneuvering capability, at least when driving with smaller speeds.

Referring to Fig. 4 showing another modification of our invention the motor casing 72, with the propeller 71 on its front end and attached to the rudder shaft 73, is provided with a nozzle ring 79, which is fastened to the flat joint pieces 76 and 77 and which extends beyond the tops of the propeller blades 71. By said nozzle ring the water conditions around the propeller are improved. The joint pieces 76 and 77 are slightly bent so that they capture the helical motion of the water coming from the propeller; this causes the helical motion component of the resultant speed of the water stream to change to an axial direction and to be employed for shearing.

According to another modification of our invention, which is illustrated in Fig. 6, the motor 82 with its propeller 81 is installed into a towing boat 89, for which purpose there is provided solely the rudder plate 85, which can be turned through the rudder shaft 83 by means of the rudder helm 84. In this example the motor casing 82 is attached to the rudder plate 85, preferably in such manner that the rudder plate is in one line with the main axle of the motor. Said motor is supplied with three phase A. current by the cable 86, which is imbedded in the rudder shaft 83 and ends at a source of current, e. g. a three phase A. C. generator driven by a diesel motor.

According to the assembly shown in Fig. 5, the passive rudder effect is partially made active, as the normal rudder has been kept on in its original size and the motor of the propeller is installed into this present rudder plate, whereas in the assemblies according to Figures 3 and 4, in which the main rudder effect is produced by the active propeller rudder, relatively small emergency rudder plates 76 and 77 are provided.

Figure 6 illustrates a modified form of the invention in accordance with which the motor 92 (of the type shown in Fig. 1) together with its propeller 91, is mounted in a rudder plate 93, the central plane of which preferably coincides with the central axis of the motor 92. According to conventional practice, the rudder plate 93 is secured to a vertical rotary rudder shaft 94 mounted in the hull 90. The motor 92 is supplied with three-phase alternating current by an electric cable provided in the interior of the rudder shaft 94 and not shown in the drawing. Pipes 95 and 96 are connected to the casing of the motor 92 and are similar to pipes 30 of Figure 1. The upper ends of the pipes 95 and 96 are connected to a tank 97 for fresh water which is mounted in the hull of the ship above its water line 98. Due to this arrangement the interior of the motor 92 is filled with water and a continuous circular flow of the water is maintained in that cool water is conveyed to the motor by the pipe 95 and is conducted back to the tank 97 when heated by the operation of the motor. The circular flow provides for a good lubrication of the bearings of the motor 92 and removes the heat arising during operation of the motor. In order to improve the conditions of flow, the propeller 91 is enclosed by a nozzle ring 99 provided in a corresponding groove of the rudder plate.

The spirit of the instant invention may also be realized in other combinations of its constructive features, within the scope of our claims without departing from the spirit of our invention. It is, therefore, to be understood that our invention is not to be limited to the specific details shown and described.

Having thus described our invention our claims are:

1. In a device for propelling a ship, in combination with a propeller, a motor housing adapted to be filled with water, an electric induction motor of the squirrel cage type comprising a stator connected to the housing and comprising field windings having waterproof insulation, a rotor enclosed by said stator, and a shaft carrying said rotor and said propeller; journal bearings and thrust bearings carried by and within said housing and carrying said shaft, said housing having passages formed therein to permit access of water to the bearings for lubrication, and means attaching said housing to the hull of the ship at the stern and below the water-line.

2. In a device for propelling a ship, in combination with a propeller, a motor housing adapted to be filled with water, an electric induction motor of the squirrel cage type comprising a stator connected to the housing and comprising field windings having waterproof insulation, a rotor enclosed by said stator, and a shaft carrying said rotor and said propeller; journal bearings and thrust bearings carried by and within said housing and carrying said shaft, said housing having passages formed therein to permit access of Water to the bearings for lubrication, and means rotatably attaching said housing to the hull of the ship at the stern and below the water-line.

3. In a device for propelling a ship, in combination with a propeller, a motor housing adapted to be filled with water, an electric induction motor of the squirrel cage type comprising a stator connected to the housing and comprising field windings having waterproof insulation, a rotor enclosed by said stator, and a hollow shaft carrying said rotor; another shaft situated within said hollow shaft and carrying said propeller, means coupling said two shafts, journal bearings and thrust bearings carried by and Within said housing and carrying said shaft, said housing having passages formed therein to permit access of water to the bearings for lubrication, and means attaching said housing to the hull of the ship at the stern and below the water-line.

4. In a device for propelling a ship, in combination with a propeller, a motor housing adapted to be filled with water, and having an elongated stream-lined shape, a propeller hub connected with said propeller and constituting a part of the stream-lined housing, said propeller hub tapering toward the end of the housing, the diameter of the propeller being at most 2.5 times the diameter of the motor housing, an electric induction motor of the squirrel cage type comprising a stator connected to the housing and comprising field windings having waterproof insulation, a rotor enclosed by said stator, and a shaft carrying said rotor and said propeller; journal bearings and thrust bearings carried by and within said housing and carrying said shaft, said housing having passages formed therein to permit access of water to the bearings for lubrication, and means attaching said housing to the hull of the ship at the stern and below the water-line.

5. In a device for propelling a ship, in combination with a propeller and a steering member attached to the ship, a motor housing adapted to be filled with water, an electric induction motor of the squirrel cage type comprising a stator connected to the housing and comprising field windings having waterproof insulation, a rotor enclosed by said stator, and a shaft carrying said rotor and said propeller; journal bearings and thrust bearings carried by and within said housing and carrying said shaft, said housing having passages formed therein to permit access of water to the bearings for lubrication, and means attaching said housing to said steering member.

6. In a device for propelling a ship, in combination with a propeller, a motor housing adapted to be filled with water, and having elongated stream-lined shape, a propeller hub connected with said propeller and constituting a part of the stream-lined housing, said propeller and propeller hub being situated in front of said housing, an electric induction motor of the squirrel cage type comprising a stator connected to the housing and comprising field windings having waterproof insulation, a rotor enclosed by said stator, and a shaft carrying said rotor and said propeller; journal bearings and thrust bearings carried by and within said housing and carrying said shaft, said housing having passages formed therein to permit access of water to the bearings for lubrication, and means attaching said housing to the hull of the ship at the stern and below the water-line.

7. In a device for propelling a ship, in combination with a propeller, a protruding bearing post of streamlined shape attached to the hull of the ship, a rudder stock journalled in said post, a motor housing adapted to be filled with water, profiled plates attached to the housing and serving as rudder blades, an electric induction motor of the squirrel cage type comprising a stator connected to the housing and comprising field windings having waterproof insulation, a rotor enclosed by said stator, and a shaft carrying said rotor and said propeller; journal bearings and thrust bearings carried by and within said housing and carrying said shaft, said housing having passages formed therein to permit access of water to the bearings for lubrication, and means attaching said housing to said rudder stock.

8. In a device for propelling a ship, in combination with a propeller, a motor housing adapted to be filled with water, rudder blades located above and below the housing and connected therewith, a nozzle ring attached to said plates, an electric induction motor of the squirrel cage type comprising a stator connected to the housing and comprising field windings having waterproof insulation, a rotor enclosed by said stator, and a shaft carrying said rotor and said propeller; journal bearings and thrust bearings carried by and within said housing and carrying said shaft, said housing having passages formed therein to permit access of water to the bearings for lubrication, and means rotatably attaching said housing to the hull of the ship at the stern and below the water-line.

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